import React, { Component } from 'react'

export default class Son extends Component {
    state = {
        num: 888
    }
    render() {
        const { num } = this.state
        const { fn } = this.props
        return (
            <div>
                <h4>
                    我是子组件 -- { num }
                </h4>
                <button onClick = { () => {
                    fn(num)
                } }>调用</button>
            </div>
        )
    }
}
